text: /*-
   * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * $FreeBSD: head/sys/net80211/ieee80211_phy.h 193072 2009-05-29 23:39:16Z sam $
   */
  
  #ifndef _NET80211_IEEE80211_PHY_H_
  #define _NET80211_IEEE80211_PHY_H_
  
  #ifdef _KERNEL
  /*
   * IEEE 802.11 PHY-related definitions.
   */
  
  /*
   * Contention window (slots).
   */
  #define IEEE80211_CW_MAX	1023	/* aCWmax */
  #define IEEE80211_CW_MIN_0	31	/* DS/CCK aCWmin, ERP aCWmin(0) */
  #define IEEE80211_CW_MIN_1	15	/* OFDM aCWmin, ERP aCWmin(1) */
  
  /*
   * SIFS (microseconds).
   */
  #define IEEE80211_DUR_SIFS	10	/* DS/CCK/ERP SIFS */
  #define IEEE80211_DUR_OFDM_SIFS	16	/* OFDM SIFS */
  
  /*
   * Slot time (microseconds).
   */
  #define IEEE80211_DUR_SLOT	20	/* DS/CCK slottime, ERP long slottime */
  #define IEEE80211_DUR_SHSLOT	9	/* ERP short slottime */
  #define IEEE80211_DUR_OFDM_SLOT	9	/* OFDM slottime */
  
  /*
   * DIFS (microseconds).
   */
  #define IEEE80211_DUR_DIFS(sifs, slot)	((sifs) + 2 * (slot))
  
  struct ieee80211_channel;
  
  struct ieee80211_rate_table {
  	int		rateCount;		/* NB: for proper padding */
  	uint8_t		rateCodeToIndex[256];	/* back mapping */
  	struct {
  		uint8_t		phy;		/* CCK/OFDM/TURBO */
  		uint32_t	rateKbps;	/* transfer rate in kbs */
  		uint8_t		shortPreamble;	/* mask for enabling short
  						 * preamble in CCK rate code */
  		uint8_t		dot11Rate;	/* value for supported rates
  						 * info element of MLME */
  		uint8_t		ctlRateIndex;	/* index of next lower basic
  						 * rate; used for dur. calcs */
  		uint16_t	lpAckDuration;	/* long preamble ACK dur. */
  		uint16_t	spAckDuration;	/* short preamble ACK dur. */
  	} info[32];
  };
  
  const struct ieee80211_rate_table *ieee80211_get_ratetable(
  			struct ieee80211_channel *);
  
  static __inline__ uint8_t
  ieee80211_ack_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
  {
  	uint8_t cix = rt->info[rt->rateCodeToIndex[rate]].ctlRateIndex;
  	KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
  	return rt->info[cix].dot11Rate;
  }
  
  static __inline__ uint8_t
  ieee80211_ctl_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
  {
  	uint8_t cix = rt->info[rt->rateCodeToIndex[rate]].ctlRateIndex;
  	KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
  	return rt->info[cix].dot11Rate;
  }
  
  static __inline__ enum ieee80211_phytype
  ieee80211_rate2phytype(const struct ieee80211_rate_table *rt, uint8_t rate)
  {
  	uint8_t rix = rt->rateCodeToIndex[rate];
  	KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate));
  	return rt->info[rix].phy;
  }
  
  static __inline__ int
  ieee80211_isratevalid(const struct ieee80211_rate_table *rt, uint8_t rate)
  {
  	return rt->rateCodeToIndex[rate] != (uint8_t)-1;
  }
  
  /*
   * Calculate ACK field for
   * o  non-fragment data frames
   * o  management frames
   * sent using rate, phy and short preamble setting.
   */
  static __inline__ uint16_t
  ieee80211_ack_duration(const struct ieee80211_rate_table *rt,
      uint8_t rate, int isShortPreamble)
  {
  	uint8_t rix = rt->rateCodeToIndex[rate];
  
  	KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate));
  	if (isShortPreamble) {
  		KASSERT(rt->info[rix].spAckDuration != 0,
  			("shpreamble ack dur is not computed!"));
  		return rt->info[rix].spAckDuration;
  	} else {
  		KASSERT(rt->info[rix].lpAckDuration != 0,
  			("lgpreamble ack dur is not computed!"));
  		return rt->info[rix].lpAckDuration;
  	}
  }
  
  /*
   * Compute the time to transmit a frame of length frameLen bytes
   * using the specified 802.11 rate code, phy, and short preamble
   * setting.
   *
   * NB: SIFS is included.
   */
  uint16_t	ieee80211_compute_duration(const struct ieee80211_rate_table *,
  			uint32_t frameLen, uint16_t rate, int isShortPreamble);
  /*
   * Convert PLCP signal/rate field to 802.11 rate code (.5Mbits/s)
   */
  uint8_t		ieee80211_plcp2rate(uint8_t, enum ieee80211_phytype);
  /*
   * Convert 802.11 rate code to PLCP signal.
   */
  uint8_t		ieee80211_rate2plcp(int, enum ieee80211_phytype);
  #endif	/* _KERNEL */
  #endif	/* !_NET80211_IEEE80211_PHY_H_ */
  